- Email: [email protected]
Influences of model peptides on phospholipid membrane organization and dynamics: A FTIR study
S72
285
287
INFLUENCES OF MODEL PEFTIDES ON PHOSF?iOLIPlD MEiUliRANE ORGANIZATlON AND DYNAhtICSzAFTlRSTVDY &&$, P. Sassi*, and C. Rossi* ?? Istituto di Chimica e Tecnologia de1 Farmaco, Universita’ de@ Studi di Pen@, Via del Lice0 1,06123 Perugia di Chimica-Fisica, Dipartimento di Chimica, **Laboratorio Universita’ de@ Sludi di Pen@, Elce di sotto 8,06123 Pert@ Leucinostatins, a novel family of peptides characterized by interesdng antimycotic properties, seem to be very suitable compounds
for the present study; in fact they promote the transport of both monoand divalent cations through the plasma membrane of mouse thymocytes. This unspecific&y of action coupled with earlier findings showing that Leucinostatin A (Leu A), the most abundant member of the family, causes membrane damage, suggested that this molecule might interact primarily with the lipid constituents of biological membranes because of its a-helical conformation and its highly hydrofobic character. In order to obtain more insight into LeuAphospholipid interactions, we investigated the conformational changes induced by the peptide on model membrane by using Fourier Transform Infrared (PTIR) spectroscopy. Specifically, temperature
dependent center of gravity shift and bandwidth of CH2 stretching vibrations (symmetric and antisymmetric) were used to monitor gelliquid phase transition of the bilayer in both multi- and large unilamellar vesicles. L.euA liposomaldispersions,formed by DPPC and DMPC,were studied at diierent lipid/peptide molar ratio WJ:~, 155:1,5~1) in order to estimate the interaction effects on both gel and liquid phase, as weU as on gel-liquid transition. The results indicate that the peptide interacts with the phospholipid acyl chains shifting the phase transition mid-point and altering the conformational state of both gel and liquid crystalline phases. In view of possible LeuA targeting by liposomal carriers, such knowledge is of critical importance for the rational design of any peptide containing liposomes formulations.
Mechanistic assessment of In vivo lontophoretic process : a study about the structuml and physiologlcal changes induced by the electrical current
L. Rodrirmes,P.Pinto,N.GaIego,L. Pereira,AAfooso, H.Gon&es, Labomtay of EIpmbm&l Phy&egy 6 L&leratrwy Ofcuhneous Eiokgy UCTF - Faculdade de Farmslcia da Univenidade de Lisboa Av.das Fops Armadas 1600 Lisboa PORTUGAL Iatroducioa. Iontophoresis is a long well known technique used to deliver compound5 across the sldn under the influence of a direclly applied electrical canent. No matter the aecanmlated knowledge some questions still subsi* sp&slly regarding electrical current effects on cutaneous physiology Folltig previous studies the authors developd an in viva model in order to eontribate to i&m@ the overall mechanistic explanation involved, studying the effeots ($ysio&kaI and morphological) following the application of a direct elect&al current (DC) on skin surface, maintainingthe subjects as near as possible from the normal Mdwid ad Methods. The potocol was developed using guinea-pig females (n=lZO) sedated with Kc&amine(1011&g). Experimentswere carriedout in a closed chamber with rigorous room temperature and humidity control. Ektrical stimulation perfotmed with a CFP Stimulator using silver electrodes. Trans-epi&mal Water Loss (TEWL), Qpacitance” changes, and superficial pH, were directly determined by refkreneed methods. Complementary analysisinvolved hkro-circulatory changes, optical and ele&oa-scan micmscopy and high-resolution (2OMHz) sonog0phic aaalysis, performed before, during electrical stimulation and on recovering period Statistics involved variance analysis (F test) and pimd t-tit test. Sigaificance level p< 0.05 was adopted Resalts and Cooelusion: The present results clearly demonstrate that Iontophoresis do affect skin physiology basically involving the transient enlargernest of intercellular spaces aad revealed by the significant early increase of TEWL. Indepsn&mly of say other alterations emerging 85 a consequence of fontophoresis, these seem to be consistently reversible, suggesting that a clear madulation of cutaneous permeability through electrical cumnt is possible with no persistent morphological and/or stmctuml changes involved.
288
286 Focusing on the biological impact of a low concentration Sallcylic Acid topical formulatlon L. Rodrimms, P .Pintn, H.G~I&w,M. Torres-Marques Laboratory of Cosmetology 65 Dermophannacy UCTF - Faculdada de Farnkla da Univenidade de Lisboa PORTUGAL 1600 Lisboa Av.das FOP+%Armadas Jntroducion. Sehaceoas gland hypemecretionrepresent a major complicante factor particularly important in the mild to moderate forms of acne which still motivate significant research on fhe field aiming to find more and better therapeuticaltools able to contribute to this dysknction. Recently,sakylic acid has heen rediscovered as a preferential and particularly efktive substance topically applicable to a wide range of epidermal lesions, &pending on the concentration used. In the present work the aulhon tested the impact on normal skin’s physiology of low concentration (25) sakylic acid included in o/w emulsions which is a particularly important aspecl regarding the control of sebacemu gland activity. Material aad Metfmds. The pmtocol was devekqxd in young bamaa volunteers, bath sexes, preseatiag a generally healthy cutaneous condition (n=L2) Experiments were carried out ia a closed chamber with rigorous room temperahue and humidity control, choosing the ventral aspat ofboth forearms and the facial frontal mid-line as anatomical testing sites. Epidennal water balance was characterized through dynamical analysis using, as indicators Trans-epidnmal Water Loss (TEWLJ and capacitance changes. Lipidical removal capacity and relative cleansing mildness were also assessed by evaluation of the lipid related compounds quantified through a eolodmetric method (Sebmneter) over the skin before and atIer formulation’s application. Statistics involved vsrisncc analysis (P test) and paired t-studentlest. Signifkanfe level p< 0.05 was adopted. Resalts aad Coaclusloa: The obtpiaed muIts clearly suggest that salicylic acid considerably affects normal cutaneous physiology.- Its well known queralolytic eapaeity may be present even ia these concentrationjustifying the superficial hydration increase, without clinkally dk-emi%le ititancy. Also, fmm the cleansing potential evaluation, results support this perspective since lipidical removal is assured with significant mildness.
ENHANCEMENT OF DISSOLUTION RATE AND BIOAVAILABILITY OF SULFAMETHOXAZOLE BY COMPLEXATION WITH CYCLODEXTRINS lcilide SAEiip! and Nurten &DEMtR Ankara University, Faculty of Pharmacy, Pharmaceutical Technology Depatrment, 06 100 Tandogan, Ankara, TURKEY Sulfonamides are bacteriostatic agents that are systemically used in treatment and prevention of bacterial infections. Even though their oral absorptions are good, as their solubility is low in GI fluids they particularly manifest bioavailability problems among individiuals. In this study sulfamethoxazole was chosen as an active material which is the member of the sulfonamide group. In order to increase the bioavailability of sulfamtihoxazole solid dispersions with different type of cyclodextrins were prepared by kneading and coprecipitation methods. The physical mixtures were also prepared for comparision. The rates of release of the active material from the resulting complexes were determined from dissolution studies using paddle method. Inclusion complexation was confumed by the results from the studies of X-Ray Diffraction, Differential Scanning Calorimetry and Infrared Spectroscopy. The formulation which was decided as ideal was studied I2 subjects. They were given the selected formulation orally, after overnight fast. Urinary excretion rates were followed for 24 hours. Urine analyses were carried out by using Bratton-Marshall Method. The bioavailability of powder form of active material were also studied in the same manner for comparision. As a result of this study it was found that bioavailability of sulfamethoxazole was significantly increased by inclusion of cyclodextrins in the formulations.
285
287
INFLUENCES OF MODEL PEFTIDES ON PHOSF?iOLIPlD MEiUliRANE ORGANIZATlON AND DYNAhtICSzAFTlRSTVDY &&$, P. Sassi*, and C. Rossi* ?? Istituto di Chimica e Tecnologia de1 Farmaco, Universita’ de@ Studi di Pen@, Via del Lice0 1,06123 Perugia di Chimica-Fisica, Dipartimento di Chimica, **Laboratorio Universita’ de@ Sludi di Pen@, Elce di sotto 8,06123 Pert@ Leucinostatins, a novel family of peptides characterized by interesdng antimycotic properties, seem to be very suitable compounds
for the present study; in fact they promote the transport of both monoand divalent cations through the plasma membrane of mouse thymocytes. This unspecific&y of action coupled with earlier findings showing that Leucinostatin A (Leu A), the most abundant member of the family, causes membrane damage, suggested that this molecule might interact primarily with the lipid constituents of biological membranes because of its a-helical conformation and its highly hydrofobic character. In order to obtain more insight into LeuAphospholipid interactions, we investigated the conformational changes induced by the peptide on model membrane by using Fourier Transform Infrared (PTIR) spectroscopy. Specifically, temperature
dependent center of gravity shift and bandwidth of CH2 stretching vibrations (symmetric and antisymmetric) were used to monitor gelliquid phase transition of the bilayer in both multi- and large unilamellar vesicles. L.euA liposomaldispersions,formed by DPPC and DMPC,were studied at diierent lipid/peptide molar ratio WJ:~, 155:1,5~1) in order to estimate the interaction effects on both gel and liquid phase, as weU as on gel-liquid transition. The results indicate that the peptide interacts with the phospholipid acyl chains shifting the phase transition mid-point and altering the conformational state of both gel and liquid crystalline phases. In view of possible LeuA targeting by liposomal carriers, such knowledge is of critical importance for the rational design of any peptide containing liposomes formulations.
Mechanistic assessment of In vivo lontophoretic process : a study about the structuml and physiologlcal changes induced by the electrical current
L. Rodrirmes,P.Pinto,N.GaIego,L. Pereira,AAfooso, H.Gon&es, Labomtay of EIpmbm&l Phy&egy 6 L&leratrwy Ofcuhneous Eiokgy UCTF - Faculdade de Farmslcia da Univenidade de Lisboa Av.das Fops Armadas 1600 Lisboa PORTUGAL Iatroducioa. Iontophoresis is a long well known technique used to deliver compound5 across the sldn under the influence of a direclly applied electrical canent. No matter the aecanmlated knowledge some questions still subsi* sp&slly regarding electrical current effects on cutaneous physiology Folltig previous studies the authors developd an in viva model in order to eontribate to i&m@ the overall mechanistic explanation involved, studying the effeots ($ysio&kaI and morphological) following the application of a direct elect&al current (DC) on skin surface, maintainingthe subjects as near as possible from the normal Mdwid ad Methods. The potocol was developed using guinea-pig females (n=lZO) sedated with Kc&amine(1011&g). Experimentswere carriedout in a closed chamber with rigorous room temperature and humidity control. Ektrical stimulation perfotmed with a CFP Stimulator using silver electrodes. Trans-epi&mal Water Loss (TEWL), Qpacitance” changes, and superficial pH, were directly determined by refkreneed methods. Complementary analysisinvolved hkro-circulatory changes, optical and ele&oa-scan micmscopy and high-resolution (2OMHz) sonog0phic aaalysis, performed before, during electrical stimulation and on recovering period Statistics involved variance analysis (F test) and pimd t-tit test. Sigaificance level p< 0.05 was adopted Resalts and Cooelusion: The present results clearly demonstrate that Iontophoresis do affect skin physiology basically involving the transient enlargernest of intercellular spaces aad revealed by the significant early increase of TEWL. Indepsn&mly of say other alterations emerging 85 a consequence of fontophoresis, these seem to be consistently reversible, suggesting that a clear madulation of cutaneous permeability through electrical cumnt is possible with no persistent morphological and/or stmctuml changes involved.
288
286 Focusing on the biological impact of a low concentration Sallcylic Acid topical formulatlon L. Rodrimms, P .Pintn, H.G~I&w,M. Torres-Marques Laboratory of Cosmetology 65 Dermophannacy UCTF - Faculdada de Farnkla da Univenidade de Lisboa PORTUGAL 1600 Lisboa Av.das FOP+%Armadas Jntroducion. Sehaceoas gland hypemecretionrepresent a major complicante factor particularly important in the mild to moderate forms of acne which still motivate significant research on fhe field aiming to find more and better therapeuticaltools able to contribute to this dysknction. Recently,sakylic acid has heen rediscovered as a preferential and particularly efktive substance topically applicable to a wide range of epidermal lesions, &pending on the concentration used. In the present work the aulhon tested the impact on normal skin’s physiology of low concentration (25) sakylic acid included in o/w emulsions which is a particularly important aspecl regarding the control of sebacemu gland activity. Material aad Metfmds. The pmtocol was devekqxd in young bamaa volunteers, bath sexes, preseatiag a generally healthy cutaneous condition (n=L2) Experiments were carried out ia a closed chamber with rigorous room temperahue and humidity control, choosing the ventral aspat ofboth forearms and the facial frontal mid-line as anatomical testing sites. Epidennal water balance was characterized through dynamical analysis using, as indicators Trans-epidnmal Water Loss (TEWLJ and capacitance changes. Lipidical removal capacity and relative cleansing mildness were also assessed by evaluation of the lipid related compounds quantified through a eolodmetric method (Sebmneter) over the skin before and atIer formulation’s application. Statistics involved vsrisncc analysis (P test) and paired t-studentlest. Signifkanfe level p< 0.05 was adopted. Resalts aad Coaclusloa: The obtpiaed muIts clearly suggest that salicylic acid considerably affects normal cutaneous physiology.- Its well known queralolytic eapaeity may be present even ia these concentrationjustifying the superficial hydration increase, without clinkally dk-emi%le ititancy. Also, fmm the cleansing potential evaluation, results support this perspective since lipidical removal is assured with significant mildness.
ENHANCEMENT OF DISSOLUTION RATE AND BIOAVAILABILITY OF SULFAMETHOXAZOLE BY COMPLEXATION WITH CYCLODEXTRINS lcilide SAEiip! and Nurten &DEMtR Ankara University, Faculty of Pharmacy, Pharmaceutical Technology Depatrment, 06 100 Tandogan, Ankara, TURKEY Sulfonamides are bacteriostatic agents that are systemically used in treatment and prevention of bacterial infections. Even though their oral absorptions are good, as their solubility is low in GI fluids they particularly manifest bioavailability problems among individiuals. In this study sulfamethoxazole was chosen as an active material which is the member of the sulfonamide group. In order to increase the bioavailability of sulfamtihoxazole solid dispersions with different type of cyclodextrins were prepared by kneading and coprecipitation methods. The physical mixtures were also prepared for comparision. The rates of release of the active material from the resulting complexes were determined from dissolution studies using paddle method. Inclusion complexation was confumed by the results from the studies of X-Ray Diffraction, Differential Scanning Calorimetry and Infrared Spectroscopy. The formulation which was decided as ideal was studied I2 subjects. They were given the selected formulation orally, after overnight fast. Urinary excretion rates were followed for 24 hours. Urine analyses were carried out by using Bratton-Marshall Method. The bioavailability of powder form of active material were also studied in the same manner for comparision. As a result of this study it was found that bioavailability of sulfamethoxazole was significantly increased by inclusion of cyclodextrins in the formulations.